Do Glofish Need A Heater? (& What Temp Do They Need)

When it comes to keeping Glofish in an aquarium, there are a few key things you need to consider. One of the most important factors is temperature. So, do Glofish need a heater? In this article, not only will you find this out, you’ll also learn what happens when the temperature gets too hot or cold, and the temperature requirements of each glofish.

So keep reading to find out!

Do Glofish Need A Heater?

The well-being and longevity of your fish depend heavily on the tank’s or aquarium’s temperature. While there is a lot of consensus on the importance of things like the filter, tank, kit, and lighting, many people still question whether they need to add a heater

Glofish, like all tropical fish need a heater, to maintain the heat of their tank efficiently. Even if you live in a warm climate, it will only take one swing in temperature which could drastically drop the temperature in your tank, causing temperature shock in your fish.

On top of this, in order to maintain a comfortable temperature for the fish, a tank heater is a helpful piece of equipment. Without a reliable heating system, you can’t keep an eye on the water’s temperature or alter it to accommodate temperature-sensitive fish. Any fish species, even the most hardy, can be harmed by sudden or consistent temperature shifts.

What Temperature Do Glofish Need?

There are five main species of glofish, each of which has its own set of requirements and preferred temperature range.

Every species of glofish will have temperature requirements that vary. So here are the optimal temperature ranges for each one!

Tetras Glofish Temperature Requirements

Tetra Glofish need a heater since they are only happy when the water in their tank is between 71 and 80 degrees Fahrenheit, with an ideal temperature of around 76 degrees Fahrenheit. Adding a heater is recommended if you don’t want your colorful fish to get sleepy because this species is more active in warmer water.

There are two distinct varieties of glofish tetras, the common glofish tetra, and the long-finned glofish tetra. Both have been altered from the original black skirt tetra, also known as the black widow tetra.

Both Tetra Glofish can be kept successfully in the aforementioned temperature range. If you plan on maintaining neon tetras in a group, you’ll need a fish tank that can hold at least 15 gallons. Under ideal conditions, an adult Tetra can reach a length of three inches, and its lifespan can extend to five years.

Danios Glofish Temperature Requirements

Optimal conditions for Glofish Danios are reached at temperatures between 65 and 77 degrees Fahrenheit. Their genetic modification makes them similar to tropical fish like the Zebra Danio. Be mindful that they require a heater to maintain a reasonable temperature in the aquarium water.

In addition, keep in mind that a heater is necessary for this fish because, despite their potential eight-year lifespan with proper care, they are prone to bacterial infections. Therefore, a heater and a filter are required to keep the water at the ideal temperature and purity for the species. 

Barb Glofish Temperature Requirements

Barbs, if included in your Glofish Aquarium, need a warm environment, between 75 and 80 degrees Fahrenheit. And as you can guess, they’re closely linked to the similarly tropical Tiger Barbs. Barb Glofish are not only partial to warm water, but also need a pH level between 6.0 and 7.0 to thrive.

Because of their susceptibility to Ich, keeping them in clean water at the optimal temperature is crucial. If you keep barbs, purchasing a heater is a good choice, as it will make maintaining a healthy environment for your fish much less of a hassle.

Betta Glofish Temperature Requirements

Like other tropical fish, Betta Glofish requires warm water (78-80 degrees Fahrenheit) to survive and grow. Betta glofish need a water heater since the water temperature in the tank must be kept within a narrow range. Additionally, they need a pH between 6.8 and 7.0. 

 If you want to keep these fish healthy, you’ll need a heater and a filter. They don’t mind being alone and may survive in a tank as small as five gallons. Bettas are often kept in small, specially designed tanks with built-in filtration systems (such as the Glofish Betta Aquarium Kit). That’s why people frequently forget they need a heater in the first place. 

However, without a submersible heater, a Betta Glofish aquarium might be quite risky for the fish. Bettas’ metabolisms can really slow down in response to cold water, which can cause intestinal problems. In addition, fish exposed to cold water may be less able to fight off bacterial and fungal illnesses.

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Shark Glofish Temperature Requirements

For inexperienced fish keepers, the Shark Glofish name could be misleading. Keep in mind that these aren’t real, tiny sharks but a close relative of the minnow family. As a result, you’ll need a heater, as the recommended temperature range for these fish is 75 to 81 degrees Fahrenheit.

A temperature of 75 degrees Fahrenheit is just one degree warmer than the average room. Therefore, a heater will likely be required if you live in a place where 75 degrees Fahrenheit is not the usual temperature in order to keep your fish happy and healthy.

What Happens If The Tank Is Too Hot For Glofish?

We know that we’ve used the word “tropical” too much in this article. While the five types of glofish need warm water, there is no doubt sometimes the water can become too hot.

Does this mean they’ll keep doing well no matter how hot the water gets? Not at all! Fish keepers are typically given a temperature range specific to their fish’s species. The water temperature must be maintained, as the following issues will develop if it rises above the optimal level.

Accelerated Metabolism

While that might not sound too terrible to you, it might lead to an increase in appetite and a stressed digestive system for your beloved fish. The organs of your fishy friend may feel the strain of a fast metabolism. Which can then cause an increased risk of permanent organ damage or death if the issue is not treated quickly.

Trouble Breathing

The ability to take in oxygen from the water is what allows glofish to survive. However, oxygen levels in the water decrease when it is heated too much. Warmer, less oxygenated water will rise to the surface, while cooler, more oxygenated water will sink to the tank’s bottom.

For this reason, fish in hot water will descend to the aquarium’s base in search of more oxygen. It’s also important to remember that suffocation can also cause lethargy, seizures, weight loss, and a lack of appetite.

What Happens If The Tank Is Too Cold For Glofish?

Cold water can be as much of an issue for Glofish as warm water. It can cause as much damage to your aquatic pet as warm water would. Your fish’s metabolism will begin to stall when the water temperature falls below the minimum required. Why? Fish, like all other cold-blooded species, must rely on their environment to keep them at a comfortable temperature. Low temperature can cause:

Slowed Metabolism

Your fish will become sluggish since their metabolism will slow down. Their appetite will decrease, and digestion will lag as a result. However, that change will be subtle if the temperature drop isn’t too dramatic.

If your fish does start eating less, you may begin to worry that it’s sick. So you should check the temperature of the water with a thermometer in such cases to make sure the temperature is perfect.

Thermal Shock 

If the water is too cold, then your glofish may go into thermal shock. symptoms, such as loss of appetite, paleness, and lethargy, are all signs of thermal shock in glofish, however, unfortunately, they’re also common across a wide range of illnesses. 

So make sure you’re using a high-quality heater to ensure the temperature doesn’t drop.

Weak Immune System

Because your fish is going to struggle more in colder water, it’s going to stress them out and put more stress on their immune system. And if they’re left for too long, they will become a lot more susceptible to diseases and illness.


Taking care of Glofish can be fun and rewarding, but is not without its challenges. Keeping them in the correct temperature with a heater is essential for proper health benefits.

Different species of Glofish require different temperatures to stay alive and thrive, so it is important to research individual species and make sure the tank is kept within the optimal range. 

If the water in the tank gets too cold, then your Glofish could suffer from slowed metabolism and thermal shock. On the other hand, if the water temperature is above what your fish need, they may become stressed and lethargic due to suffocation.

In any case, it’s best to err on the side of caution when caring for these amazing creatures! So if you’re thinking about getting some Glofish of your own, remember to invest in a reliable heater—and do your research ahead of time! 

About the author

Hey! I'm Antonio!

Betta fish keeper for over 6 years now! Since owning a betta I've also housed all kinds of tropical fish, and have seen all manner of problems and how to look after them!

If you need any advice you can always message me or better yet join the Facebook group where a community can answer your questions!

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